1. Field of the Invention
This invention relates to a cleaning device in an image forming apparatus for removing developer, dust and/or corona products adhering to a surface to be cleaned.
The image forming apparatus may be an electrophotographic copying apparatus, a micro instrument, a laser beam printer or the like. The surface to be cleaned may be the surface of an image bearing member such as a photosensitive drum, a magnetic drum or an insulating drum, or the surface of a member to which developer adheres, such as the surface of a fixing roller. The shape of the image bearing member is not limited to a drum or a roller, but may also be a belt or the like.
2. Description of the Prior Art
Heretofore, in an image forming apparatus utilizing the electrostatic photographic process, it has been the usual practice to charge the surface of an image bearing member by a plurality of corona discharges for the purposes of charging the image bearing member and transferring a toner image to a transfer member. Therefore, the molecules in the air may be varied by the corona discharge to produce substances such as nitrogen oxides. These corona products may adhere to the surface of the image bearing member and under a high-humidity environment, the resistance of the surface of the image bearing member may be reduced to give rise to an adverse effect such as blurring the electrostatic latent image formed on the surface of the image bearing member.
Heretofore, in order to eliminate the above-mentioned adverse effect, there have been proposed a method of heating and drying the image bearing member and a method of disposing a so-called cleaning blade and also rotating a friction roller made of silicone rubber or like material while urging it against the surface of the image bearing member, thereby removing the corona products from the surface of the image bearing member.
Particularly, the latter method is an excellent method in that it has a stable effect in the long-time use of the image bearing member and that it is also effective in removing the substances in a transfer member such as paper adhering to the surface of the image bearing member or toner fused on the surface of the image bearing member.
Any residual toner removed from the photosensitive medium by the cleaning blade is transmitted onto the friction roller, is scraped off therefrom by a scraper and is discharged by a screw, and in this process, toner has been suspended within a cleaning device and has scattered out of the cleaning device. As a method for decreasing such scattering, it would occur to mind to make the lengths of the cleaning blade and the friction roller sufficiently great relative to the width of the image area, but actually it has often been impossible in view of the requirement for compactness of the device to make said lengths sufficiently great. Accordingly, difficulties have remained concerning the countermeasure for said scattering.